Improvement in the manufacture of iron tubing



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Manufacture of Iron T ubing. No. 36,140. 'Patented/wg. 1251862.

.WANN M. .MNH

UNITED STATES PATENT OFFICE.

JOSEPH H. COTTON, 'OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN THE MANUFACTURE OF IRON TUBING.

To aZZ whom it may concern.-

Be it known that I, JOSEPH H. COTTON, of Boston, Massachusetts, have invented certain new and useful Improvements in the Manufacture of Iron Tubing; and I do hereby declare that the following isa full, clear, and exact description of the same, reference being had to the annexed drawings, making a part of this specification, in which- Figure No. 1 is a section of mandrel. Fig. No. 2 is asection of mandrel with piece of tube ready to be drawn. Fig. No. Sis a front View of die. Fig. No. 4 is a section of die.

My improvement is applied in the following manner: I take short and thick. iron tubes madein any of the usual modes for boiler-tubes. After annealing them they are dipped into dilute acid and then scoured, then intoabath of melted tin and tinned thoroughly both inside and outside. They are then drawn cold through dies upon steel mandrels, increasing them much in length, while decreasing them in thickness, until the desired length and lthickness are attained.

Tubes drawn in this manner are much su# perior to those made in any of the usual modes, being perfectly cylindrical and smooth upon both their inner and outer surfaces. The fiber,

ductility,and malleabi'lity of theiron are much what I claim as new, and desire to secure by Letters Patent, is-

Coating iron tubes as set forth and subsequently drawing them while cold through dies, in the manner specified, thus producingatube perfectly cylindrical and smooth upon both .its inner and outer surfaces.

- JOS. H. COTTON.

Witnesses:

E. B. BUOKINGHAM, FRANK B. COTTON. 

